Mogadishu (Reuters) - Ethiopian troops and Somali government forces killed 17 al Shabaab rebels on Thursday after the Islamist militants blocked a road in southern Somalia and stole goods, a regional official said.

Mohamed Abdi Mayow, the governor of Bakool region, said the al Qaeda-linked militants had been blocking trucks carrying supplies to Hudur for seven weeks and had unloaded goods from at least five lorries.

"They blocked all supplies and unloaded goods. This led to the fierce fighting and we swept al Shabaab from the area, Mayow told Reuters by telephone from Hudur.

Ethiopian forces pushed into southern Somalia in November to open up a third front against the militants, who are also fighting Ugandan and Burundian troops around Mogadishu and Kenya's military along its southern border.

While they have squeezed al Shabaab out of some areas, the militants hold large chunks of central and southern Somalia and pose the biggest threat to efforts to stabilize the country after two decades of civil conflict.